Wednesday, July 27, 2011

I Like Birds (or: Prehistory and the Press redux)

It's good to open with a song.

Who doesn't like birds, what with their penetrating stares from glassy eyes that so perfectly mask the quiet intelligence at work? (Except in the case of ostriches. Boy, they're stupid. Tasty, though. Tasty and dangerous.) But what the devil is a bird, exactly?

Obviously I'm bringing this up in relation to a paper by Xu et al that's been getting quite a lot of attention. Rather predictably the media has already been fudging the science; in fact, even Nature News made a bit of a hash of things.
After analysing the traits present in Xiaotingia and its relations, Xu and his colleagues are suggesting that the creatures bear more resemblance to the dinosaurs Velociraptor and Microraptor than to early birds, and so belong in the dinosaur group Deinonychosauria rather than in the bird group, Avialae. (Source)
The suggestion seems to be that 'birds' are something quite separate and distinct from 'dinosaurs', whereas the consensus view among palaeontologists has for years been that Aves (or if you prefer, Avialae) is a clade within the Dinosauria. Avialae is just as much a 'dinosaur group' as Deinonychosauria, and it would have been pretty hard to tell apart primitive examples of either in life (and so it is proving with the fossils).

The Guardian's also chosen to sensationalise the idea that Archaeopteryx might be a feathered nonavian dinosaur, rather than a bona fide bird. "The fossil Archaeopteryx may not have been one of the earliest birds but just another feathered dinosaur," we are told. But what's the difference? Birds are 'just' feathered dinosaurs, and Xu et al do not dispute this. The article (written by our old friend Ian Sample) goes on to talk of birds as if they are something separate from dinosaurs. The simple fact is that they are not. Of particular irritation is this paragraph:
If archaeopteryx [sic] was a dinosaur, this means flight evolved at least four times in vertebrates: in reptiles, birds, dinosaurs, and most recently in bats. (Source)
According to various theories currently floating around, avian and nonavian dinosaurs in Paraves (the clade that includes deinonychosaurs and avians) could have a common flying/gliding/arboreal ancestor (or maybe even a ground-dwelling one), or various nonavian and avian dinosaurs could have evolved and lost flight over millions of years. Some people even think that the distinction has become quite meaningless, and will readily call Velociraptor a bird. Then there's that use of the word 'reptile'. Presumably, Dr Sample meant 'pterosaurs'. I suppose we'll let him off on that one.

The BBC are at it too.

Birds are dinosaurs. They are not special, or different, just because they're still alive and don't fit pop culture expectations of a giant, reptilian monster with huge fangs. The sooner newspaper journalists learn this, and stop misleading the public, the better.

1 comment:

  1. This is one of my favourite Eels albums. "I Like Birds" was the first song I learned how to play on the guitar.

    my brother e-mailed me today with a link to this article, too. I was equally unimpressed. With all the things being discovered in China, wasting ink on whether or not the archaeoteryx is the oldest bird is ridiculous.

    Keep up the good work - I love to lurk!


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